The present invention concerns a component or composite part for enduring high thermal stress, such as a divertor plate used as a xe2x80x9cfirst wallxe2x80x9d in a fusion reactor. The composite, at least in some sections, is made of tungsten or a tungsten alloy.
Components for enduring high thermal stress used, for example, as the xe2x80x9cfirst wallxe2x80x9d in a fusion reactor, are, as a rule, constructed as a composite. The side facing the plasma is used as a heat shield and is constructed of materials having a high melting point and good thermal conductivity, such as graphite, or metal materials, such as tungsten or molybdenum. The component acting as the heat shield is produced either as a massive, block-shaped heat sink or as an actively cooled heat sink, with a cooling agent flowing there through made of a material having good thermal conductivity. Such later materials have a lower melting point than the heat shield, and can be comprised of copper or copper alloy.
Tungsten or tungsten alloys would appear to be very well suited as components for enduring high thermal stress, particularly for use as a divertor in fusion reactors, because of their high mass number, good thermal properties, and because they have among the highest melting point of all metals. However, tungsten and tungsten alloys have not been widely used, to now, as components for enduring high thermal stress because these materials can be brittle, having a comparatively high ductile/brittle transition temperature. Hence, these materials are extremely susceptible to fissures when enduring thermal shock stress.
The purpose of the present invention, therefore, is to provide components or composite parts used for enduring high thermal stress, for example, divertor plates used as the xe2x80x9cfirst wallxe2x80x9d in a fusion reactor, which are made, at least in some sections, of tungsten or a tungsten alloy.